Daily Trivia #492 Index Blues

Contributed by Pranshuman! Life saver!

The X Index is a guide published by The Economist magazine to compare the currencies of different countries.It does so by looking at the price of a X, which is available in more than 100 countries. Thus, a X in the U.S. costs $4.07 whereas in China it costs $2.27, using nominal exchange rates. After 25 years, India has finally made it to the X Index. X index is a simplistic way to demonstrate purchasing power parity, a theory that says that the exchange rate between two countries should move toward “correct value,” which would make the price of a basket of products the same in both countries.

Interestingly, X is not available in India, probably because it may 'hurt' some people. Instead, it is replaced here by Y.
ID X and Y.

For the number cruncher types, here are a few graphs.